playing career. >> reporter: roger clemens left u.s. district court after a pretrial hearing. inside the courtroom, the superstar pitcher learned that his case may get some help. the judge says he may not allow damaging testimony about steroids from clemens' former teammates. it would be a win for the baseball great who is facing six felony charges. >> let me be clear, i have never taken steroids. >> reporter: prosecutors say clemens lied under oath when he testified before congress in 2008. their star witness will be brian macknamy, clemens' former trainer. >> i told the truth about steroids. i injected those drugs into the body of roger clemens at his direction. >> reporter: he claims he even kept the used needles, which will be key evidence at trial. some of clemens' former teammates, including felly pitcher andy pettitte admit they received injections. >> but the jury may never hear that testimony from pettitte and other players. the judge says he will likely not allow it because it could unfairly influence the jury. >> reporter: cl